AEI State Housing Supply Legislative Tracker

Data is limited to cities with a population of at least 50,000. City population totals use the higher of the 2023 ACS 1-Year or 5-Year survey population estimates. Under a minimum density of 6 units per acre, we assume lot sizes must be at least 7,260 sq.ft. (43,560 / 6) in order to be eligible for a lot split.

Data is limited to land within subject jurisdictions, defined as either (1) a municipality that has a population of at least 1,000, as reported by the state demography office, and is within a metropolitan planning organization or (2) the portion of a county that is within a census designated place with a population of 40,000 or more, as reported in the most recent decennial census, and within a metropolitan planning organization. Municipality population totals from the Colorado state demography office were obtained from the SDO's data resource page. Population totals from the decennial census use the 2020 census. Data is further limited to land within Colorado Water and Sanitation Districts, obtained from the Colorado Geospatial Portal. At a minimum lot size of 2,000 sq.ft., we assume a distribution of lot sizes that yields approximately 12 homes per acre, on average. For lot splits, we assume that the minimum lot size applies; thus, a lot must be at least 4,000 sq.ft. in order to be eligible for a lot split.

Data is limited to cities with a population of at least 1,000 within federally designated metropolitan planning organizations. City population totals use the higher of the 2023 ACS 1-Year or 5-Year survey population estimates.

For this analysis, the 5,000 sq.ft. cap applies to new residential subdivisions and lot splits, corresponding to Options #1-2 of the AEI Housing Center Playbook, respectively. For lot splits, a lot must be at least 10,000 sq.ft. under the 5,000 sq.ft. minimum lot size cap to be eligible for a lot split, and only lot splits of up to three are allowed. All results are the sum of Options #1 and #2 and assume that a public water and sewer system is available. Connecticut's Department of Public Health and Department of Energy and Environment Protection publish geospatial data for land with public water and sewer access (water access data available here, and sewer access data available here).

Data is limited to Hawaii's urban districts and excludes all land within FEMA designated special flood hazard areas. At a minimum lot size of 1,200 sq.ft., we assume a distribution of lot sizes that yields approximately 13.5 homes per acre on average. For lot splits, a lot must be at least 2,400 sq.ft. to be split under a minimum lot size of 1,200 sq.ft.

Data is limited to Hawaii's urban districts and excludes all land within FEMA designated special flood hazard areas. At a minimum lot size of 1,200 sq.ft., we assume a distribution of lot sizes that yields approximately 13.5 homes per acre on average. For lot splits, a lot must be at least 2,400 sq.ft. to be split under a minimum lot size of 1,200 sq.ft.

See the Idaho state Playbook Option #3 (flexibility to build homes near jobs) total: https://heat.aeihousingcenter.org/toolkit/housing_playbook.

See the 3-unit conversion total for Idaho state on the AEI Housing Center Light Touch Density Price Chart: https://heat.aeihousingcenter.org/toolkit/ltd_chart.

Data is limited to cities with a population of at least 10,000. City population totals use the higher of the 2023 ACS 1-Year or 5-Year survey population estimates. SB 1353 does not specify explicit minimum lot sizes but bans minimum lot sizes that would effectively block duplex construction. For this purpose, we assume that a lot size of 10,000 sq.ft. would block duplex construction, and that duplexes are typically about 1,500 sq.ft. each.

At a minimum lot size of 2,500 sq.ft., we assume a distribution of lot sizes that yields approximately 11.5 homes per acre on average. Lots eligible for conversion must be between 2,501 and 5,000 sq.ft. to be split into four lots, 5,001 and 7,500 sq.ft. to be split into six lots, and > 7,500 sq.ft. to be split into 8 lots. Lots <= 2,500 sq.ft. are considered ineligible for lot splits.

See the ADU total for Illinois state on the AEI Housing Center Light Touch Density Price Chart: https://heat.aeihousingcenter.org/toolkit/ltd_chart.

For Option #1, data excludes homes with a living area greater than or equal to 3,000 sq.ft. and lot size greater than the 90th percentile for small homes with a living area less than 3,000 sq.ft. (about 15,700 sq.ft. lot sizes). This excludes about 10% of homes built in subdivisions from 2000-2024 in Kansas and captures homes that are too large to fit on a 3,000 sq.ft. lot and on lots too large that a builder wouldn't downsize to a 3,000 sq.ft. home. For Option #2, data excludes homes with a living area greater than or equal to 3,000 sq.ft. At a minimum lot size of 3,000 sq.ft., we assume a distribution of lot sizes that yields approximately 11 homes per acre on average.

For Option #1, we include all areas of counties with a population greater than or equal to 20,000. At a minimum lot size of 3,000 sq.ft., we assume a distribution of lot sizes that yields approximately 11 homes per acre on average. For Option #3, as in the Playbook, we include only cities with a population greater than or equal to 10,000. County population totals use the higher of the 2023 ACS 1-Year or 5-Year survey population estimates.

See the Kentucky state Playbook Option #3 (flexibility to build homes near jobs) total: https://heat.aeihousingcenter.org/toolkit/housing_playbook.

See the ADU total for Kentucky state on the AEI Housing Center Light Touch Density Price Chart: https://heat.aeihousingcenter.org/toolkit/ltd_chart.

Assumes any existing lot may be split into two lots. See the total at a maximum number of conversion units per parcel of two for Kentucky state on the AEI Housing Center Light Touch Density Price Chart: https://heat.aeihousingcenter.org/toolkit/ltd_chart.

Growth area designations are made at the municipal level through each town's comprehensive plan but typically correspond to urban areas. Thus, as a proxy for growth areas, we use the Census's urban land designations. Maine does not publish statistics on county-level public water and sewer access. Thus, as a proxy for public water and sewer access, we use tract size and density. Tracts with 95% or more of all homes are on a half-acre or greater and an average density of less than or equal to 1.5 homes per acre are excluded from all calculations. At minimum lot sizes of 5,000 sq.ft. and 1,250 sq.ft., we assume a distribution of lot sizes that yields approximately 10 and 13.5 homes per acre on average.

Limits to counties with a population of 150,000 or greater. County population totals use the higher of the 2023 ACS 1-Year or 5-Year survey population estimates.

Limits to counties with a population of 150,000 or greater. County population totals use the higher of the 2023 ACS 1-Year or 5-Year survey population estimates.

For Option #1, we assume that there is no change in the lot sizes of single-family detached (SFD) homes, but 25% of SFD land is reserved for middle housing (i.e., single-family attached). We limit to subdivisions with at least 20 lots. In Maryland, 72% of new residential subdivisions built from 2000-2024 had at least 20 lots. Thus, the Option #1 projection is adjusted by 72%. For Option #2, we limit viable infill conversion lots to vacant lots that existed before Jan. 2015. All results are the sum of Options #1 and #2 and assume that a public water and sewer system is available. Maryland does not publish statistics on county-level public water and sewer access. Thus, as a proxy for public water and sewer access, we use tract size and density. Tracts with 95% or more of all homes are on a half-acre or greater and an average density of less than or equal to 1.5 homes per acre are excluded from all calculations.

About 40% of properties in Maryland's commercial zones are 1/2 mile from major public transit. Thus, this projection is 40% of the Maryland state Playbook Option #3 total (7,300 * 0.4 = 2,920).

See the ADU total for Maryland state on the AEI Housing Center Light Touch Density Price Chart: https://heat.aeihousingcenter.org/toolkit/ltd_chart.

For this analysis, the 10,000 sq.ft. cap applies only to new residential subdivisions, corresponding to Option #1 of the Playbook. For lot splits, up to 5 are allowed on land with public water and sewer access, and up to 3 are allowed on land without water and sewer access. ADUs are assumed to a by-right use on all land regardless of water/sewer access. The Massachusetts Department of Environmental Protection publishes water and sewer utility service boundaries. We mapped homes in our property-level data to these boundaries for the Option #2 analysis.

For this analysis, the 10,000 sq.ft. cap applies only to new residential subdivisions, corresponding to Option #1 of the Playbook. For lot splits, up to 5 are allowed on land with public water and sewer access, and up to 3 are allowed on land without water and sewer access. ADUs are assumed to a by-right use on all land regardless of water/sewer access. The Massachusetts Department of Environmental Protection publishes water and sewer utility service boundaries. We mapped homes in our property-level data to these boundaries for the Option #2 analysis.

For Option #1, data is limited to properties with public water and sewer access. Michigan does not publish data on public water and sewer access; thus, as a proxy for public water and sewer access, we use tract size and density. Tracts with 95% or more of all homes are on a half-acre or greater and an average density of less than or equal to 1.5 homes per acre are excluded from all calculations. At a minimum lot size of 1,500 sq.ft., we assume a distribution of lot sizes that yields 13 homes per acre on average.

For Option #1, data is limited to properties with public water and sewer access. Michigan does not publish data on public water and sewer access; thus, as a proxy for public water and sewer access, we use tract size and density. Tracts with 95% or more of all homes are on a half-acre or greater and an average density of less than or equal to 1.5 homes per acre are excluded from all calculations. At a minimum lot size of 1,500 sq.ft., we assume a distribution of lot sizes that yields 13 homes per acre on average.

County population totals use the higher of the 2023 ACS 1-Year or 5-Year survey population estimates. Data is limited to counties with a population greater than 700,000.

See the ADU total for Nebraska state on the AEI Housing Center Light Touch Density Price Chart: https://heat.aeihousingcenter.org/toolkit/ltd_chart.

This bill allows ADUs, duplexes, and townhomes in residential zones and residential in commercial with no restrictions. Since it doesn't specify a minimum lot size, we defaulted to our Playbook projection for Options #2 and 3 for New Mexico state. See the New Mexico Playbook here: https://heat.aeihousingcenter.org/toolkit/housing_playbook.

This bill stipulates that counties cannot establish minimum lot sizes. Therefore, we defaulted to our Playbook projections for Options #1 and 3 for New Mexico state, excluding ADUs. See the New Mexico Playbook here: https://heat.aeihousingcenter.org/toolkit/housing_playbook.

This bill contains drafting ambiguities that impact the projection. We assume that multifamily housing (including duplexes and townhomes) in both residential and commercial zones must be within 1/4 mile of a major public transit stop. We interpret the bill's allowable minimum density of 10 units per acre for multifamily as implying a minimum lot size of no greater than 4,356 sq.ft. About 10% of properties in Nebraska's commercial zones are 1/4 mile from major public transit. Thus, the Option #3 projection is 10% of the Nebraska state Playbook Option #3 total (150 * 0.1 = 150).

See Option #3 total for North Carolina state Playbook here: https://heat.aeihousingcenter.org/toolkit/housing_playbook.

All estimates are limited to municipalities with a population above 50,000 in counties with a population above 275,000. North Carolina does not publish recent data on public water and sewer access. Thus, as a proxy for public water and sewer access, we use tract size and density. Tracts with 95% or more of all homes are on a half-acre or greater and an average density of less than or equal to 1.5 homes per acre are excluded from all calculations. At a minimum lot size of 1,200 sq.ft., we assume a distribution of lot sizes that yields 13.5 homes per acre on average. For Option #2, we assume lot splits up to 10 are permitted if each lot meets the 1,200 sq.ft. minimum lot size.

See the ADU total for North Carolina state on the AEI Housing Center Light Touch Density Price Chart: https://heat.aeihousingcenter.org/toolkit/ltd_chart.

Data on public water and sewer access are obtained from the Rhode Island Geographic Information System Water Supply Districts and Sewered Areas. For minimum lot sizes of 2,500 and 5,000 sq.ft., we assume a distribution of lot sizes that yields 11.5 and 8 homes per acre on average. For Option #3, data is limited to municipalities with a population greater than 40,000. To account for the requirement that municipalities provide a minimum of 30% of land in commercial areas for residential overlays, we multiply each eligible municipality's Option #3 total by 30%.

This bill permits residential in commercial on 75% of commercial land. Thus, we calculated the impact as 75% of the Virginia state Playbook Option #3 total (9,300 * 0.75 = 6,975). See the Virginia Playbook here: https://heat.aeihousingcenter.org/toolkit/housing_playbook.

Data is limited to cities with a population above 20,000 or parcels within a designated metropolitan planning area. The Option #3 total is then adjusted downward by 25%, reflecting the bill's permitting residential in commercial on 75% of commercial land.

See the ADU total for Virginia state on the AEI Housing Center Light Touch Density Price Chart: https://heat.aeihousingcenter.org/toolkit/ltd_chart.

See the ADU total for Virginia state on the AEI Housing Center Light Touch Density Price Chart: https://heat.aeihousingcenter.org/toolkit/ltd_chart.

Data is limited to municipalities only (i.e., incorporated cities, towns, or consolidated city-counties). Unincorporated county land is excluded from the total.

Data is limited to municipalities only (i.e., incorporated cities, towns, or consolidated city-counties). Unincorporated county land is excluded from the total. The Option #2 ADU total is then adjusted downward by 65%, as ADUs are a permitted use on only 35% of residential land under this bill.